Constant flow stoker



Oct. 9, 1962 J. F. TURNER ET AL 3,057,309

CONSTANT FLow sToxER '7 Sheets-Sheet l Filed Aug. 18. 1959 Lfkloft-Prfom l N VEN TORS ATTORNEY I dames /'Tu-rne'r,

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CONSTANT FLOW sToxER Filed Aug. 18. 1959 7 sheets-sheet 2 INVENTOR v.(xm" @$41k l s v MAfMuAL QRAJ'E CQN'rRoI.

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Oct. 9, 1962 .J.F. TURNER ET AL CONSTANT FLow sToKER 7 Sheets-Sheet 4Filed Aug. 18, 1959 Oct. 9, 1962 Filed Aug. 18, 1959 J. F. TURNER ETALCONSTANT FLOW STOKER 7 Sheets-Sheet 5 S5 INVENTORS dames E Turner,

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ATTORNEY Oct. 9, 1962 J. F. TURNER ET AL CONSTANT FLOW STOKER Filed Aug18, 1959 Oct. 9, 1962 J. F. TURNER ETAl. 3,057,309

CONSTANT FLOW sToKER Filed Aug. 18, 1959 7 Sheets-Sheet '7 United StatesPatent 3,057,309 Patented Oct. 9, 1962 Oiice 3,057,309 CONSTANT FLOWSTOKER James F. Turner, William H. Bartman, and Clarence Henry Smith,Jr., Baltimore, Md., assignors to Flynn &

Emrich Company, Baltimore, Md., a corporation of Maryland Filed Aug. 18,1959, Ser. No. 834,477 Claims. (Cl. 110-8) This invention relates to arefuse burning furnace or incinerator stoker. Such furnaces are used to-burn market refuse, Waste animal and vegetable matter and garbage andthe like from municipalities, and industrially they are used to burncrates, boxes, paper and the like. It is an improvement on the furnaceshown in the patent to Turner et al., No. 2,777,406 of January 15, 1957and embodies the use of much of the structure shown therein. A singleunit like that shown in the drawing of the present invention is adaptedto destroy approximately three hundred tons of material in twenty-fourhours. Furnaces for larger consumption would be side by side duplicatesof the unit shown.

The objects of the present invention involve the development of afurnace of high capacity which operates continuously and in which theautomatic mechanisms can be readily varied from centrally operatingpoints, depending upon the nature of the material to be destroyed andthe conditions of operation of the furnace at the time. Also theseparate stages of the furnace may be individually controlled manuallywithout affecting the setting of the automatic mechanisms. Also theoperation of any one or more of the furnace stages or all the stages ofthe rfurnace could be stopped entirely without affecting the automaticsystem of control.

Other objects and advantages of the invention will be apparent from thefollowing description and the accompanying `drawings forming a parthereof and in which:

FIGURE 1 is a side elevational view of one unit of the furnace of thisinvention.

FIGURE 2 is a fragmentary side elevational view in greater detailshowing two stages of the furnace -bed and the drop-olf or nose gratebetween them.

FIGURE 3 is a fragmentary horizontal sectional 'View of the grate barsand their mounting and driving connections.

FIGURE 4 is a fragmentary side elevation showing the top part of thecontrol head and operating levers for manual operation and the cut-offfor the fluid to the drive cylinders.

FIGURE 5 is a horizontal sectional view of the control head, showing theautomatic control valves, taken on the line 5 5 of FIGURE 4.

FIGURE 6 is a vertical sectional view of the control head, taken on theline 6 6of FIGURE 7.

FIGURE 7 is a vertical sectional view on line 7 7 of FIGURE 6.

FIGURE 8 is a vertical sectional view on line 8 8 of FIGURE 6.

FIGURE 9 is a fragmentary horizontal plan view of the control head withthe top part removed.

FIGURE 10 is a vertical fragmentary sectional view on line 10-10 ofFIGURE 7.

FIGURE 11 is a vertical longitudinal sectional view through the solenoidfour-way valve which controls the automatic admission of fluid to therespective control lines.

FIGURE l2 is a diagrammatic view of the furnace grate bar drivecylinders and the means for operating them.

FIGURE 13 is a diagrammatic view of the cam sets on the automatic timer.

In the drawings similar numerals refer to similar parts throughout theseveral views,

The incinerator furnace of this invention is generally illustrated inFIGURE l and has a charging hopper 1 and a feed chute 2 which isrelatively high to permit the accumulation of the material therein tosuch a degree as to avoid a back `draft up the chute while the hopper isbeing substantially continuously charged. Should this continuouscharging be interrupted, a covering as shown, should be placed over thehopper to prevent creating a natural draft so that the material wouldnot catch lire in the chute. The material in chute 2 passes to grate 3and the grates 3, 4, and 5 are of identical construction, like thoseshown in detail in FIGURES 2 and 3 and they have between them drop-offor nose grate sections 6. Beneath each section or stage of the grate areash collectors 7 leading to a common chute 8 entering the nal ashdisposal bins 9 which also receive the ash directly from the finalburning grate 5 continuously and bins 9 have a guide 10 therein whichmay be thrown to direct the ash to a leg of the bin not then beingemptied.

In the construction shown air is preferably admitted to the undersurface of the burning grates 4 and 5 and to the drop-off sections 6 butair is not admitted to the grate section 3 under the feed chute 2, toavoid ignition of material thereon within the chute. The material is fedfrom the hopper of a depth regulated by the cover chute top wall 11 andas it flows from the hopper grate to the first burning grate 4 it turnsover and is broken up. It is broken up from the packing imparted to itin the hopper 1 and chute 2, so that it res readily as it passes downthe burning grates 4 and 5. It is again turned over at the verticallystationary nose grate between grate sections 4 and 5 and this cascadingover the drop-off sections breaks open any masses of the materialtheretofore unbroken.

The grate lifting cylinders 12 and 13 are mounted in pairs on the framework 14 of the furnace structure and each section or stage of the grateshas separate pairs of pistons and cylinders for their operation, eachpair being of identical construction and when several units of thefurnace are required for increased capacity, the drive units of adjacentunits are preferably placed in a common aisle between the units forconvenient separate manual operation should that be desired.

The pistons and cylinders forming hydraulic motors are made generallylike those in the patent to Turner et al., No. 2,752,756, July 3, 1956.As shown in this patent the pistons are double ended and driven fromeach end with the cross-head connected at the center. The forward headof the piston in the upper cylinder 12 is shown at 15. The cross-head 16on the piston of the upper cylinder is connected to link 17 which inturn is connected by rockerarms 18 to shaft 19 which extends across thegrates of the stage illustrated in FIGURES 2 and 3. Shaft 19 throughmeans of rocker-arms 20 is connected to pull rods 21 which in turn areconnected to connecting bars 22 to which alternate grate bars 23 areconnected. The lower cylinder cross-head 24 through similar link 25,rocker-arm 26, shaft 27, rocker-arms 28, pull rods Z9 and connectingbars 30 operates the alternate grate bars 31, pushing them upwardly onthe left hand movement of the piston as shown in FIGURE 2. When thepistons return to their normal rest position, the grates return to theirnormal rest posi- 3 tion. The laternate movement or sequence of thegrates feeds the refuse from the base of the chute 2 to the rstcombustion stage 4 and then to the stage 5, each operation of the gratesmoving the refuse forward a denite increment. This movement'not onlymoves the refuse forward but it agitates it, keeps it porous, welldistributed and free burning. Oneoperation for both groups of alternategrates is termed a cycle of grate operation. By controlling the resttime of the pistons between the cycles, the progress of the burning massdown the grates can be regulated. Pumps 32 driven by motors 33 furnishthe hydraulic power for the cylinders. A pressure line 34 is divided,one branch leading to central opening 35 of the valve of FIG- URE l1,and the other branch has branches 36 leading to the control head 37 atthe end of the cylinders of each stage as shown in FIGURE l2; likewiseleading to this control head are branches 38 and 39 of control lines 49and 41 leading from the intermediate side cavities, 42 and 43 of thesolenoid four-way valve shown in FIGURE l1 and the valve itself 44 isnormally centered by means of springs 45 at each end. Likewise at eachend of the valve is a non-magnetic pin 46 and a laminated iron core 47which is pulled centrally upon magnetization of the solenoid coil 48.There is a manual pin 49' likewise at each end, pressure upon whichmoves the valve 44 olf center. Pressure from the pumps 32 through line34 enters the center cavity 35 of the solenoid valve. The solenoid valvealso has spaced exhaust passages 50 connected to line 51 leading throughthe spring loaded check valve 52 back to the exhaust line and the pumpreservoir. When the valve 44 is centered the branch control lines, 38and 39, then serving as exhaust lines from the control heads, are openthrough the solenoid valve to the exhaust 50 line 51 and valve 52. Eachtime the four-way solenoid valve is operated oil pressure is admitted tothe control head 37 of the cylinders. This control head includes anon-of valve 53 operated by handle 54 which must be turned to the onposition as shown in -solid lines in FIGURE 7 to connect with controlpressure lines 40 and 41, to permit the pressure from the controlpressure lines to pass therethrough. The main pressure line 34 throughits branches 36 is connected to the bottom of each cylinder control head37 where the oil pressure is admitted through passage 55 to the centercavity 56 of each of two spool type spring olfset valves 57 as shown inFIGURE 6. The lower spool valve is shown in its normal rest positionwith the spring 58 extended. In this position as shown in FIGURE 6 theroil pressure goes through passage 59 for the lower valve and passage 60for the upper spool valve, when that valve is in the reversed positionfrom that illustrated in FIGURE 6, to the rear of the cylinders andpistons as above described, respectively, to the lower and uppercylinder as shown in this FIGURE 6; with the lower spool valve at restpressure is admitted to the front of the lower cylinder f 13. In thisposition the pressure on the front of the lower cylinder will lower thegrates of the attached set down to their normal rest position. In FIGURE2 they are up, just before being lowered since their control lower spoolvalve is thrown, ready to lower them.

Pressure oil from the main pressure line 34 is also ported past the mainspool valves through the top of the control head 37 and enters thecenter cavity 61 of the on-off valve 53 as shown in FIGURE 7 throughpassage 62. Oil from control lines 38 and 39 passes through ports 63 and64 in the on-olf valve to the manual valve 65 operated by handle 66 andthrough ports 67 and 68 respectively in the manual valve, when inneutral position shown in FIGURES 5, 6 and 7.

Pressure oil from the main pressure line 34 through the central opening56 in the control head 37 is admitted to the cylinders for theiroperation when the spool valves 57 are in their left hand position asshown for the upper valve in FIGURE 6. The pressure with the Valve 57 inthe position shown goes `through circular passage 69 in the control headand along passage 70 therein and through passage 71 between cylinders 12`and 13 as shown in FIGURES 6 and 8 to the rear of the cylinders. Thispassage 71 is connected to drive the upper piston 15 through apassageway in the rear cylinder head, there being a hollowed projection72 on the rear cylinder heads -to form this passageway into the righthand end of the cylinders as shown in FIGURE 2. The admission of thepressure to the right end of the cylinders as shown in this FIGURE 2elevates the grate bars 31 as above described. A similar drive passagefor the piston in the lower cylinder 13 is shown in FIGURE 6, fromcircular passage 73, angular passage 74 and longitudinal passage 75between the cylinders 12 and 13 to the rear head of cylinder 13 where asimilar passage in a hollowed projection of that head provides for theadmission of pressure uid to the rear of the piston in the lowercylinder 13 to raise the alternate set of grate bars 23, upon theadmission of pressure fluid to the rear end of this piston.

Upon the activation of the solenoid coil 48 moving the four-way solenoidvalve shown in FIGURE ll passage 35 is connected to the control line 38through movement of the valve 44 to the left as shown in FIGURE ll andthis admits pressure through line 3S through the ori-off valve passage63 therein and the manual valve, pasage 67 thereof, and through passage76 in the control head 37 to the right side of that housing as shown inFIGURE 6` to the operating piston cavity 77 of the operating piston 7Sand this pressure overcomes the spring 53 to move the spool valve 57 tothe left similar to the position shown for the upper spool Valve in thisFIGURE 6, which in turn then passes pressure from the pressure lines 34and 36 to the rear of the lower cylinder 13 to move its piston forwardand thereby effect the raising of the set of grate bars 31 as shown inFIGURE 2.

Movement of the solenoid four-way valve 44 in the opposite directionpasses pressure from the control line 39 through the passages 64 and 68of the on-off valve and manual valve and passage '79 in the control head37 to the operating piston cavity 80, upon the introduction of pressuretherein the operating piston 81 is moved to the left as shown in FIGURE6 which permits the application of pressure to the rear end of thepiston 15 in upper cylinder 12 and the raising of the alternate set ofgrate bars 23.

Exhaust chambers S2, 83, 84 and 85 are located near the extremities ofthe respective spool valves 57 and the respective pairs of these exhaustchambers are connected by passages 86 to the vertical passage 87 leadingto the branch exhaust line 88 of the main exhaust line 89, back to thepump reservoir.

Upon the return of the lower spool valve 57 to its right hand restposition the exhaust from the rear end of the cylinder 13 passes throughpassageway 73 in the control head housing 37 through passageways 84, 86and 87 to the exhaust line 38. Each control line from the control headhousing 37 is in turn used as an exhaust line through that control headback to the pump reservoir through the passages above described.

If for any reason power is cut off the control or if the hydraulic pumpsshould fail during operation the grates will immediately return to theirnormal rest positions because all valves are spring returned to theirnormal rest positions and the residual pressure in the exhaust line 51is always held by the check valve 52 to an adequate pressure to servethis purpose. This same result applies if the electric current shouldfail for the operation of the fourway solenoid valve because it too isspring centered.

To produce the sequence operation of alternate sets of grates by themovement of the solenoid valve back and forth, a program timing devicelike that shown in FIGURE l2 may be utilized. It will be understood thatas long as pressure remains in the respective control lines therespective set of grates will be elevated and when that pressure isremoved the spring centered spool valves 57 will Operate and cut off thepressure from the pressure lines and return the raised grates to theirlowered fuel supporting position. They remain up with the maintenance ofpressure on the control lines and that pressure must therefore bemaintained the required length of time after raising them and pressuremust be left off the alternate control line a sufficient period of timeto allow the raised set of grates to lower. Electric energy to operatethe solenoid four-way valve 44 at regular intervals as described abovemay be supplied through a set of cams. As shown in FIGURE 13, the camsmay all be assumed to be carried on a common shaft of synchronous motor90 shown in FIGURE l2. As illustrated the cams make a completerevolution in twelve seconds or a quarter revolution in three seconds.The cams have a large diameter section 91 and a small diameter section92. The first cam set 93 closes the contacts 1A and 1B shown in FIGURES13 and 12 and thereby energizes the left hand coil as shown in FIGURE 12and movement of valve 44 to the right caused by the energizing of theleft hand coil passes pressure through the control lines to the uppercylinders. The current on this coil remains closed for three secondswhich is the length of time required to raise one set of grate bars toprogress the material thereover. Cam 93 then opens its circuit andcircuits through the timer remain open for another three seconds toallow the grate bars of the raised set time to lower. After the lapse ofthese six seconds cam 94 by its larger diameter section closes thecurrent through contacts 2A and 2B shown in FIGURES 13 and l2 and thesecond set of grate bars is raised during the passage of a period ofthree seconds and then through the passage of another period of threeseconds allowed time to lower, thus alternately moving four-way valve 44back and forth and if the synchronous motor 90 be maintained inoperation, this alternate movement of the grate bars will continue incycles of ve per minute.

It is, however, generally desired not to have precisely alternatemovements of the grate bars in this timed sequence but rather to varythe time of dwell between movements of the grate bars and for thispurpose a repeat cycle timer is employed. One of these is available fromthe Wilson Company of Huntington, West Virginia, which is their ModelNo. 2 made in 1959 and it is diagrammatically illustrated at 95 inFIGURE 12 of the drawing. This unit forms a time controlled relaycircuit and is in line with the circuit to drive the synchronous motor90 of the program timer, causing it -to stop and restart in accordancewith the opening or closing of contacts in the relay of the repeat cycletimer. As shown in this timer 95, electric line L1 is connected to itand to the left hand side of the synchronous motor 90, or line L1 of theprogram timer. Line L2 passes to contact 2 then 4 of the timer 95 andthen to the magnetically controlled arm at the upper right hand cornerof this timer. When current is not owing through the magnetic coil, notshown, the movable arm by spring tension is pulled against contact 3 ofthe relay, which in this application is not used. When the magnetic coilis energized, it causes the movable arm 4 of the relay to overcome thespring tension and make contact with contact 5 of the relay and thispoint is connected to contact 5 of the timer 95 and a line L2 is furtherconnected to line L2 of the program timer. It will be seen that therepeat cycle timer 95 controls the time the synchronous motor 90 isoperated, and consequently the time the cam carrying shafts run.

It is important that the alternate movement of the grates be maintainedto assure proper operation and for that purpose each cycle of operationshould be complete and for that purpose again, the rotating shaft of thesynchronous motor 90 should start and stop at the same point shouldelectric energy be interrupted to lines L1 and L2 and reconnected. Toaccomplish this purpose a third cam set 96, FIGURE 13, is provided witha relatively short time that current is cut from contacts 3A and 3B asshown in FIGURES 13 and l2 but during that time these contacts are openand the syncronous motor stops and the springs of the various valvesreturn the grates to their rest position. The cam set 96 may be manuallyadjustable on its cam shaft to assure that the cam stops at the samepoint each time the program timer ceases to activate the coils of thefour-way valve.

The number of cycles of operation to accomplish optimum furnace resultsis determined by the time relay contacts 4 to 5 of the repeat cycletimer 95 remain closed or are open. The time of the on cycle, as well asthe time of the off cycle, is readily adjustable by the range switchesindicated in FIGURE 12. The Wilson No. 2 repeat cycle timer has anoff-on switch which allows current and voltage to be applied to thetransformer indicated, and from its secondary windings with theresistor-capacitor circuit and tube type 0D3 provides the power supplyof the circuit of the duo triode tube 12AU7. Each triode section of the12AU7 has its plate and grid circuit capacitor coupled as indicated onthe diagram, FIGURE 12. Varying the range switch setting of the offcycle and the Vernier adjustment will vary the off cycle of the repeatcycle timer in steps from a minimum of 01 seconds to maximum of 1000seconds. The on cycle is variable by setting its corresponding rangeswitch and Vernier. The setting of the on cycle and the ot cyclecontrols through the grid to plate capacitance coupling the time currentflows through its corresponding half of the tube 1ZAU7. The coil of therelay R is in the plate circuit of one triode section of the 12AU7. Whencurrent flows through this magnetic coil, contacts 4 to 5 are closed.When current is prevented from flowing the coil has no magnetic fieldand the contacts open.

By setting the range switch on cycle and its Vernier of the repeat cycletimer to allow an on time of 30 seconds, will allow the program timercam shaft to make 3 full revolutions, since it is over 24 seconds andunder 36 seconds, and cause the cycles of grate operation.

By setting the range switch off cycle and its Vernier for an olf time of12() seconds, interrupts the current flow to the program timer for thisamount of time, deactivating the grates for this period of time.

The cycle of operation will repeat until a readjustment of the rangeswitches with their respective Verners, or the off-on switch is turnedto off.

There will be times when it is dsirable, due to the character of thematerial to either prevent a stage of grates fro moperating for a shortspace of time or to activate theg rates of a stage when the uni happensto be in the off cycle. The manual operating valve and on-off valvesabove described serve this purpose best. In FIGURES 5 and 7 the on-oifvalve is shown open or on. Should this valve be rotated clockwise asshown by'the dotted line position of the handle in FIGURES 4 and 7,ports 63 and 64 will be closed, so will the passage of oil from cavity61 be cut off. Should either piston of the cylinders be in process ofraising the grates at this time, oil pressure in any of the ports isexhausted through port 97 extending the length of the on-oif valve andit drains through the end of that housing through pasageways 98 and 99to the exhaust valve cavity 83, particularly as shown in FIG- URE 6. Thecavity 100 likewise drains oil from the housing of the manual valve 65to that of the on-oif valve 53. While the on-off valve is in its closedposition above described no operation of the pistons in either directioneither manually or by means of the solenoid four-Way valve can takeplace until this on-off valve is first opened by counterclockwiserota-tion to its original on position. With `this on-olf valve in its onposition but with the repeat cycle timer in the olf position, operationof any cylinder may be accomplished by the oil pressure from the mainpressure line in the central cavity 101 being received from the centercavity 61 of the on-otf valve. This pressure through cavity 101 isineffective when the manual valve is in neutral position as shown inFIGURES 5, 6 and 7. When the handle 66 of this valve is turned to theleft as shown in FIGURES 4, and 7, oil ows from the center cavity 101 ofthe valve through the off-set port 102 to passage 76 and the operatingpiston cavity 77, moving the operating piston 7S and then the lowerspool valve 57 and the lower piston in cylinder 13. When the handle 66is moved to the right as shown in FIGURES 4, 5 and 7, oil passes fromthe central cavity 101 to the off-set port 103 through passage '79 topiston cavity 80 causing the upper piston 15 in cylinder 12 to beoperated. Returning -the manually operated valve to neutral again blocksoft these valve ports i102 and 103 of oil supply from the pressure lineand connects the ports `67 and 68 for automatic operation by thefour-way solenoid valve.

The ability to operate manually without interference with the automaticcontrols and without the necessity of adjustment before and/ or aftermanual operation enables the operator to take immediate action at thedesired locations of the equipment without the necessity of upsettingthe worked out automatic control setting.

What is claimed as new and is desired to be secured by letters patentis: y

1. A furnace for burning refuse comprising a plurality of tandem sets ofalternately actuated stoker bars which in normal position form aforwardly and downwardly inclined supporting surface for the refuse,downwardly inclined supporting means `for said bars, a furnace frame onwhich said supporting means are mounted, said bars being movably mountedso that they can be tilted forwardly to advance the refuse and thenretracted and means including reciprocating bars connecting thealternate bars of each set together to be so moved together, individualhydraulic motors mounted on said frame and connected to each set of saidreciprocating bars to operate the same, a source of fluid pressureconnected by conduit lines to each motor, manually controlled means tooperate each motor independently of the others from said source,separate pressure control conduit lines leading from said source to eachmotor, means in said control conduit lines to connect the motors of theseparate sets of bars to the pressure conduit line to pass pressuresimultaneously through the pressure and control conduit lines forrepeated predetermined periods of time -to raise the bars to materialforwarding position and means to lower all the bars to materialsupporting position upon failure of tfluid pressure from said source,means to cut o the connection of the control conduit lines to the motorsupon operation of the manually controlled means.

2. A furnace for burning refuse comprising a plurality of tandem sets ofalternately actuated stoker -bars which in normal position form aforwardly and downwardly inclined supporting surface for the refuse,downwardly inclined supporting means for said bars, a furnace frame onwhich said supporting means are mounted, `said bars being movablymounted so that they can be tilted forwardly to advance the refuse andthen retracted and means including reciprocating bars connecting thealternate bars of each set together to be so moved together, individualhydraulic motors mounted on said frame and connected to each set of saidreciprocating bars to operate the same, a source of fluid pressure, adouble ended hydraulic motor connected to each reciprocating bar, toraise and lower the respective sets of Stoker bars upon `admission offluid to` the respective ends of the motors, conduit lines connectingthe source to each motor, adjustable automatic means connected byconduit lines from said source to said motors to admit the fluid to therespective motors of each set in a predetermined sequence and forpredetermined periods of time for both motor activation and motor rest,manually controlled means Within the pressure conduit lines between thesource and motors to yadmit the uid to the respective ends of themotors, means connected with the manually controlled means to makeineiective the operation of the automatic means without disturbing theadjustment for the predetermined periods thereof. f

3. A furnace fork burning refuse comprising a plurality of tandem setsof alternately actuated stoker bars which in normal position form aforwardly and downwardly inclined supporting surface for the refuse,downwardly inclined supporting means for said bars, a furnace frame onwhich said supporting means are mounted, said bars being movably mountedso that they can be tilted forwardly to advance the refuse and thenretracted and means including reciprocating bars connecting thealternate 'bars of each set together to be so moved together, individualhydraulic motors mounted on said frame and connected to each set of saidreciprocating bars to operate the same, a source of fluid pressure, adouble ended hydraulic motor connected to each reciprocating bar, -toraise and lower the respective sets of stoker bars upon ad-mission offluid to the respective ends of the motors, conduit lines connecting thesource to each motor, a spring set sliding valve and housing thereforadjacent each motor, the housings and motors having passages thereinconnecting the valves of the respective motors to said source, each saidvalve when set by its spring admitting uid from the source to itsrespective motor to return the Stoker bars to material supportingposition, and means to repeatedly move the valve to pressure Stoker barraising position for predetermined intervals and at predetermined times.

4. A furnace for burning refuse comprising a plurality of tandem sets ofalternately actuated stoker bars which in normal position form aforwardly and downwardly inclined supporting surface for the refuse,downwardly inclined supporting means for said bars, a furnace frame onwhich said supporting means are mounted, said bars being movably mountedso that they can be tilted forwardly to advance the refuse and thenretracted and means including reciprocaitng bars connecting thealternate bars of each set together to be so moved together, individualhydraulic motors mounted on said frame and connected in pairs to eachset of said reciprocating bars to operate the same, a source of uidpressure, conduit lines connecting the source to each pair of motors, acontrol head having normally closed valves therein on each pair ofmotors, electrically actuated hydraulic control means connected byadditional conduit lines between said source and each control head toopen said valves to admit pressure from said source through said firstnamed conduit lines and to the respective motors of each set forrepeated predetermined periods of time for both motor activation andmotor rest, said last named means including means to restore 4the stokerbars to supporting position upon `failure of electric current thereto.

5. A furnace for burning refuse comprising a plurality of tandemforwardly and downwardly inclined stages of sets of alternately actuatedstoker bars, downwardly inclined supporting means for said bars, afurnace frame on which said supporting means lare mounted, the stagesbeing vertically substantially spaced to cause refuse from the upperstage to disintegrate in falling to the bars of the adjacent lowerstage, individual hydraulic motors mounted on said frame and connectedto the alternate sets of bars of each stage to operate the same, acommon source of uid pressure for said motors, conduit lines connectingthe source to each motor, normally closed valves on each motor in saidconduit lines, to control the pressure to the motors, common hydraulicactuating means connected by additional conduit lines from said sourceto said valves, to open the same to admit the pressure from said sourcethrough said first named conduit lines to said motors of each set with apredetermined sequence for repeated predetermined periods of time,pressure control means in said additional conduit lines to restore thebars of all the sets to refuse supporting position upon failure of thecommon actuating means.

(References on foliowing page) References Cited in the le of this patentUNITED STATES PATENTS Turner Feb. 6, 1934 Beers Mar. 12, 1935 5 KohoutMar. 15, 1938 Wiedmann May 6, 1941 Krogh et a1 Jan. 6, 1942 10 WiedmannFeb. 24, 1942 Eichler Dec. 21, 1954 Turner et a1. July 3, 1956 FOREIGNPATENTS Great Britain Sept. 23, 1935 France Feb. 16, 1942 Germany Nov.14, 1957

